Tonight (Sept. 30), the waxing crescent moon will sit simply above the brightest star within the constellation of Scorpius — Antares.
The skinny sliver of the moon that’s seen as its vibrant facet continues to show from Earth might be only a thumb’s width — about 1.5 levels — above this crimson star within the southwestern sky.
The star is often known as Alpha Scorpii on account of it being the brightest star within the constellation of Scorpius, the scorpion. At instances it has additionally passed by the identify ‘the Scorpion’s Coronary heart.’
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The star is seen as a glowing crimson pinpoint throughout summer season evenings within the Northern Hemisphere and through winter evenings within the Southern Hemisphere and has an obvious magnitude between 0.88 and 1.16. (On the magnitude scale utilized by astronomers, decrease numbers signify brighter objects. For instance, at its brightest, the planet Venus shines with a magnitude of about -4.6.)
Antares is of the 20 brightest seen stars from Earth and has cemented itself into the folklore of our ancestors.
The identify Antares comes from the Greek translation of the phrase ‘rival to Ares.’ Ares was the Greek god of conflict who would grow to be often known as Mars. Thus, the identify Antares actually means ‘rival to Mars’ referring to the planet Mars — the planet’s identify arising on account of the planet’s blood-like coloration.
This mythological rivalry pertains to the closeness within the coloration of the 2 our bodies and the truth that the our bodies go shut by one another within the sky incessantly.
Whereas the crimson coloration of Mars is the results of the rocky planet being coated by iron-rich dust and rocks which have oxidized and turned orangy as the results of water publicity.
Antares, alternatively, is a crimson supergiant star with no stable floor. As stars like the sun run out of gas for nuclear fusion the radiation stress that balances the inward drive of gravity ceases. This causes the core of the star to bear gravitational collapse.
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As this occurs, nevertheless, the outer shells of that star are nonetheless finishing up nuclear fusion — burning hydrogen and creating helium — which causes the shell to “puff out” Because the outer shell grows the center generated by nuclear fusion spreads over a bigger space.
This causes the floor of the now large star to chill which leads it to glow crimson. That is the crimson supergiant phase that Antares is at present experiencing and is one thing the sun will undergo in about 5 billion years because it swells out to across the orbit of Mars — swallowing the inner planets together with Earth.
Antares has a diameter that’s at present between 600 and 800 instances the diameter of the sun — round 588 million miles to 692 million miles (946 million kilometers to 1.114 billion kilometers) and is far cooler than the sun. It is that large floor space that accounts for its brightness.
The closeness of Mars and Antares — and Antares and the moon on Friday night for that matter — within the sky is an phantasm with the crimson supergiant lurking round 550 million light-years from Earth.
When Antares’s crimson supergiant phase involves an finish it’s going to bear additional gravitational collapses and can fuse more and more heavier parts in its core.
As it’s 11 to 14 instances the mass of the sun, Antares is very large sufficient to finish its life with a large supernova blast that can go away behind both a neutron star or a stellar-mass black hole.
Astronomers aren’t certain when precisely this supernova blast — which might be seen from Earth — might happen however it’s prone to occur inside the subsequent few hundreds of thousands of years.
Fortunately, the crimson supergiant is extremely prone to be current in time for its shut encounter with the crescent moon within the night on Friday.
